Background Osteonecrosis of the lunate bone (OLB), also known as Kienböck's disease, is a rare disorder that has been recently reported in several patients with systemic sclerosis (SSc)1, but still it is not clear if this is only a coincidence of 2 rare didsorders or whether OLB is a potentially under-recognized manifestation of SSc.
Objectives To describe the clinical features of patients with SSc seen in a Spanish tertiary care center, who develop OLB.
Methods We performed a retrospective observational study that included patients followed in our center between January 2010 and December 2015. Demographic data, clinical and laboratory features, risk factors for osteonecrosis, imaging, treatment and outcome were collected.
Results A total of 115 SSc patients were identified and 4 of them (3.47%) developed OLB. Mean age of these patients was 59.5 (range: 52–73), being all women. 2 cases were limited cutaneos SSc (lcSSc) and 2 cutaneous diffuse SSc. 3 cases showed anticentromere antibodies and 1 anti-topoisomerase I antibodies, but none presented anticardiolipin antibodies nor had previous thrombotic events. Mean disease duration was 13.5 years (range: 7–17). One patient was ex-smoker, but none had alcohol consumption, and one case was hypertensive. All patients had vascular manifestations (severe Raynaud phenomenon, digital ulcers in treatment with endothelin antagonists and perfusion of iv prostaglandins, and one case had critical digital ischemia); all the patients showed calcinosis in the upper limbs, and they also had joint involvement (50%), gastrointestinal (100%), and pulmonary (50%) manifestations. History of rolonged corticosteroid therapy at low doses (prednisone 5–10 mg/day) was present in all cases and was discontinued one year before the onset of osteonecrosis in one case. OLB was unilateral right in 3 cases and bilateral in one case. The patients presented with clinical pain and/or swelling in the affected wrist in the months prior to diagnosis of OLB, which was evidenced by simple radiography, MRI and bone scintigraphy. One of the cases also showed extensive synovitis in the affected wrist and another one developed collapse of the lunate bone with displaced fragment and edema. Treatment was surgical in 25% of the cases (proximal carpectomy), and conservativein in the rest. Among the total SSc population studied there was another case of lcSSc presenting osteonecrosis of the left tarsal scaphoid bone.
Conclusions A total of 15 cases of OLB associated to SSc have been reported to date, so it could be an underestimated disease-associated feature of SSc. It has been suggested that its etiology is linked to SSc-related vasculopathy and all our cases had evidence of severe vasculopathy. The location and vascularization of the lunate bone should be taken into account, since no case developed osteonecrosis in other common locations despite corticotherapy, and complete occlusion of the distal ulnar artery has been reported in 3 cases of the literature. The presence of pain, with or without wrist inflammation in SSc patients should make us consider OLB, which is probably more frequent than expected, especially when there is evidence of severe SSc-related vasculopathy.
Frerix M, et al. Is osteonecrosis of the lunate bone an underestimated feature of systemic sclerosis? A case series of nine patients and review of literature. Semin Arthritis Rheum. 2016;45:446–54.
Disclosure of Interest None declared